There's some nice illustrations posted on the author's twitter account.
One of the drafts for volume 1 cover. Was rejected because Leon looked like one of the potential love interests of otome game and also because Marie looks like the MC.
Also colored illustrations of the characters (only black-and-white on LN).
Volume 1 characters (colored).
Volume 2 characters (colored).
Spoiler for others:
Clarith
Gertrude
Master
Bandel
But man...Marie is so short even when compared to Angelica and Olivia. How can she handle so many
cocks men..... She would break.